1. Field of the Invention
The invention relates generally to memory systems, and more particularly to systems and methods for reducing instability and writability problems that arise from relative variations of voltages provided to logic components and memory cells.
2. Related Art
The demand for improved electronic and computing devices continually drives the development of smaller, faster and increasingly efficient devices. As transistors for these devices are scaled down, they may adopt lower operating voltages to allow them to dissipate less power. While this generally does not present problems for much of the logic in a computing device, it may cause problems with the stability and writability of memory cells such as SRAM cells that are used in conjunction with the logic.
One of the ways these stability and writability problems is typically addressed is by using an operating voltage for the memory cells (Vcell) that is slightly higher than the operating voltage of the device's logic components (Vdd). Vcell must be carefully selected, however. If Vcell is too high in comparison to Vdd, the memory cells may be too strong, and a write driver may have difficulty writing new data into the cells. If, on the other hand, Vcell is too low in comparison to Vdd, the memory cells may be too weak, and the data stored in the cells may be corrupted when the cells are read. There is therefore an optimal range for Vcell in comparison to Vdd, such that the stability and writability described above are avoided.
While it may be a relatively straightforward matter to determine the optimal range for the ratio of Vcell to Vdd, there may be variations in these voltages due to operation of the device (e.g. more or fewer components drawing power.) As each of the two operating voltages changes, the ratio between them changes, potentially resulting in the failure of write operations or the corruption of data during read operations.
It would therefore be desirable to provide systems and methods for preventing data corruption during read or write operations in systems that use different voltages for logic components and memory cells.